An innovative nanosecond time-resolved fluorescence detection technology, with the potential for simultaneously measuring multiple analytes in a single sample, will be applied to the development of a novel quantitative, high-sensitivity immunofluorimetric assay system for reproductive hormones. The project will entail development of both a prototype instrument and prototype reagents. In phase I luteinizing hormone (LH) or human chorionic gonadotropin (hCG) will be employed as a model hormone to optimize assay performance in terms of sensitivity, specificity, simplicity, speed, and precision; and to validate the feasibility of the proposed approach. In phase II, the multiple-analyte capabilities of the proposed approach will be reproductive hormones of clinical interest. The proposed immunoassay technology has the potential to non-isotopically replicate in physician's offices the capabilities of radioimmunoassay, which generally can only be performed in hospitals or large reference laboratories.